Electric switch



Aug. 19, 1958 E. H. HAHN, JR

ELECTRIC SWITCH Filed Nov. 29, 1956 IN V EN TOR. 'ZMEkMVA/I JP.

ArroR/v Y9 ELECTRIC SWITCH Elmer H. Hahn, Jr., Cleveland, Ohio, assignor to The Leece-Neville Company, Cleveland, Ohio, a corporation of Ohio Application November 29, 1956, Serial No. 625,014

10 Claims. (Cl. 200-77) This invention relates to electric switches, and as one of its objects, aims to provide a novel quick opening switch which will be of a simple, practical and economical construction. The switch construction of the present invention is applicable to various uses where a fast breaking action is desirable between the contacts and, by way of example, the novel construction is herein disclosed as embodied in a manually operable starter switch.

Another object of this invention is to provide a novel quick-break electric switch having a movable shaft and spring means for transmitting motion to a movable contact means and in Which clutch means responsive to the loading of the spring means controls shaft movement in the switch opening direction so as to produce the desired quick break between the contacts.

A further object is to provide such a quick-break electric switch in which the movement of the shaft is a linear movement and in which the clutch means is contractible and expandable for holding or releasing the shaft.

As still another object, this invention provides such a novel quick-break switch in which the clutch means comprises shoulder means on the shaft and an annular group of balls contractible into holding engagement with the shoulder means.

Additionally, this invention provides a quick-break switch of the character above indicated, in which the group of balls is contractible into holding engagement with the shaft in response to loading of the spring means and is expandable to release the shaft in response to a partial unloading of the spring means.

The invention can be further brifly summarized as consisting of certain novel combinations and arrangements of parts hereinafter described in detail, and particularly set out in the claims hereof.

In the accompanying sheet of drawings forming a part of this specification,

Fig. 1 is an axial sectional view of a quick-break electric switch emboding the present invention, the view being taken as indicated by section line 11 of Fig. 2 and with the switch in its open condition.

Fig. 2 is a transverse sectional view taken on the section line 2-2 of Fig. 1;

Fig. 3 is an axial sectional view similar to that of Fig. 1, but showing the switch in its closed condition; and

Fig. 4 is a partial transverse sectional view taken on section line 4-4 of Fig. 3.

Referring now to the drawings in greater detail, the electric switch 10 comprises in general a housing 11 having a pair of stationary contacts 12 and 13 therein, a movable shaft 14 carrying a movable contact 15, and an actuating member 16 engageable with the shaft for imparting switch closing movement thereto.

The housing 11 is provided on one side thereof with a contact chamber 17 which is closed by an insulating cover 18 having the stationary contacts 12 and 13 mounted thereon. Projecting stem portions of the stationary contacts 12 and 13 form external terminals 19 and 20 tates Patent 2,848,575 Patented Aug. 19, 1958 on the cover 18. The cover is secured in place on the housing as by suitable screws 21.

On the other side thereof the housing 11 is provided with an axial boss 23 having a guide passage 24 extending therethrough and communicating with the chamber 17. A retaining member 25 mounted on the boss 23 by means of suitable connecting screws 26 is provided at the outer end thereof with an inturned annular lip 27. The retaining member 25 cooperates with the actuating member 16 in a manner to be explained hereinafter.

The actuating member 16 comprises a sleeve portion 16a disposed in a surrounding substantially coaxial relation to the shaft 14 and a closure cap 16b threadedly en gaged in the outer end of the sleeve portion. At the inner end thereof the actuating member 16 is provided with an out-turned annular flange 28. The flanged inner end of the actuating member 16 is located in the retaining member and is axially movable in the latter. The actuating member 16 is connected with the housing 11 by the retaining member 25 and the flange 27 of the latter is engageable by the flange 28 for limiting outward axial movement of the actuating member.

The shaft 14 is axially slidable in the guide passage 24 of the housing 11 and is provided with a relatively reduced outer stem portion 30 having ahead or nut 31 on the outer end thereof. The inner end of the shaft 14 extends into the contact chamber 17 and supports the movable contact 15 in bridging relation to the stationary contacts 12 and 13. The movable contact 15 is mounted on the shaft 14 by means of an insulating bushing 32 which is slidable on the shaft and retained on the latter by the head 33a of a screw 33 which is engaged in an end opening of the shaft. A contact spring 34 surrounding the shaft 14 is disposed between the bushing 32 and a spring seat formed by a snap ring 35 engaged in an annular groove 36 of the shaft.

Movement of the shaft 14 in a downward or switchclosing direction causes the movable contact 15 to engage the stationary contacts 12 and 13 for closing of the switch. Continued movement of the shaft 14 in the switch-closing direction causes the shaft to slide through the bushing 32 and is resisted by the contact spring 34. If the movement of the shaft 14 in the switch-closing direction continues to the point where the contact spring 34 is compressed to a solid condition, this spring will then act as a stop for terminating the switch-closing movement of the shaft. The switch-closing movement is imparted to the shaft 14 by the actuating member 16, whose cap portion 16b is engageable with the head 31 of the shaft.

In accordance with this invention, the switch 10 is provided with clutch means which becomes effective on the shaft 14, when the latter has moved the contact 15 into engagement with the contacts 12 and 13, and temporarily retains the shaft in a position corresponding with the closed condition of the contacts. This clutch means is here shown as comprising an annular shoulder 38 formed on the shaft 14 and facing in a direction away from the movable contact 15, and a contractible and expandable annular group of balls 39 engageable with such shoulder.

The annular group of balls 39 is contained in an an- I nular groove 40 surrounding the shaft 14 and formed between the adjacent ends of a boss extension 23a and a thrust sleeve 41. The side walls of the groove 40 are defined by the axially opposed annular bevels 42 and 43 which are formed, respectively, on the boss extension 43 and the sleeve 41. The balls 39 are provided in suitable number such that When they are moved into a contracted condition adjacent the shoulder 38 they will constitute a substantially closed annular ring, as shown in Fig. 4.

3 A guide sleeve 45 extending substantially coaxially of the shaft 14 and mounted on the boss extension 23 forms a retainer for the annular group of balls 39. The sleeve 41 is axially slidable in the guide sleeve 45 with the annular bevel 43 of its inner end presented to the groupof balls 39. The actuating member 1'6 is disposedaround the sleeve 45 and is guided on the latter externally thereof.

An inner spring 46 surrounding the stem portion 30- of the shaft 14 and disposed between the head 31" and the sleeve 41 urges the latter in an inward axial direction. An outer spring 47 also surrounding the stem portion 30 of the shaft 14 is disposed between the sleeve 41 and the cap portion 16b of the actuating member 16. From the location just described for the inner and outer springs 46 and 47 it will beobserved that these springs are housed within the actuating member 16.

In the actuation of the switch 10, an axial movement imparted to the actuating member 16 will cause loading of the springs 46 and 47 and will bring the cap portion 16b into engagement with the head 31 of the shaft 14. Further movement of the actuating member 16 will cause axial movement of the shaft 14 to close the switch contacts and to move the clutch shoulder 38 to a position slightly beyond, and axially inward of, the annular group of balls 39 as represented in the closed condition of the switch shown in Fig. 3. When the shaft has been moved to this position, the pressure of the springs 46 and 47 will be effective on the clutch balls 39 through the bevels 42' and 43 to contract the group of balls into a holding engagement with the annular shoulder 38. The engagement of the balls 39 with the shoulder 38 temporarily retains the switch in its closed condition until a predetermined extent of outward axial movement of the actuating member 16 has taken place.

When opening of the switch is desired, the actuating force applied to the member 16 is released, whereupon the outer spring 47 imparts outward axial movement to the actuating member and as the result of which this spring becomes partially unloaded. While the actuating member 16 is being moved outwardly by the spring 47, the inner spring 46 and the contact spring 34 are both exerting forces on the shaft 14 tending to move the latter in an outward or switch-opening direction. Such outward movement of the shaft is temporarily prevented by the clutch balls 39, but when the outer spring 47 has been unloaded to a suificient extent the sleeve 41 will permit the balls to be wedged outwardly by the shoulder 38, thereby releasing the shaft for a quick outward movement thereof by the springs 34 and 46. This quick outward movement of the shaft 14 causes the desired quickbreak opening movement of the movable contact 15.

The switchopening outward movement of the shaft 14 is limited by a suitable stop provided on the housing 11 and which is here shown as comprising the annular abutment face 49 surrounding the guide passage 24. By the time that the movable contact disengages the stationary contacts 12 and 13 the contact spring 34 will be in its expanded condition, and the further outward movement of the shaft under the influence of the inner spring 46 will bring the stop Washer of the shaft 14 to a final position adjacent to, or in engagement with, the abutment face 49. If desired, a group of washers 50 made of fiber or other suitable material can be provided on the shaft 14 adjacent the stop washer 35 to constitute a bumper or a cushioning means for engagement with the face 49.

From the accompanying drawing and the foregoing detailed description, it Will now be readily understood that this invention provides a quick-break electric switch which is of a simple and highly practical form, embodying a construction comprising a relatively small number of parts adapted to be economically produced and easily assembled. It will be understood further that contractible and expandable clutch means embodied in the switch is effective on the movable shaft thereof for 4 holding or releasing the shaft in response to the action of the spring means and the movement of the actuating member. Additionally, it will be understood that when the clutch means is in the form of an annular group of balls as here provided, it will operate etliciently throughout a long period in a uniformly satisfactory manner.

Although this novel quick-break electrical switch has been illustrated and described here to a somewhat detailed extent, it will be understood, of course, that the invention. is not to be regarded as being limited correspondingly in scope, but includes all changes and modifications coming within the terms of the claims hereof.

Having thus described my invention, I claim:

1. In an electric switch, a housing having a guide passage therein, stationary contact means in said housing, a shaft axially movable in said guide passage, movable contact means engageable with and disengageablc from said stationary contact means by switch closing and switch opening axial movements of said shaft, actuating means for imparting the switch closing axial movement tosaid shaft, spring means subject to loading in response to the switch closing actuation of said shaft and to partial unloading during movement of said actuating means in the switch opening direction, said shaft having a shoulder thereon, contractible means engageable with said shoulder for temporarily restraining said shaft against switch opening movement thereof, and bevel means responsive to the loading of said spring means and being axially shiftable by the latter for contracting said contractible means into such restraining engagement with said shoulder, said contractible means being expandable by said shoulder in response to the partial unloading of said spring means for releasing said shaft for a quick switch opening actuation of the shaft by said spring means.

2'. An electric switch as defined in claim 1 in which said shoulder faces away said contact means, and in which said contractible means comprises an annular group of balls.

3. In an electric switch, a housing having a guide passage therein, stationary contact means in said housing, a shaft axially movable in said guide passage, movable contact means engageable with and disengageable' from said stationary contact means by switch closing and switch opening axial movements of said shaft, said shaft having a shoulder thereon facing away from said contact means, means defining a groove surrounding said passage including an anular bevel forming a side wall of the groove; an annular group of balls in said groove, actuating means for imparting switch closing'movement to said shaft, and spring means subject to loading during the switch closing actuation of said shaft and to partial unloading during movement of said actuating means in the switch opening. direction, said group of balls being contractible into holding engagement with said shoulder by said bevel. in response to the switch closing movement of said shaft and the loading of said spring means, said group of balls being expandable by said shoulder in response to the partial unloading of said spring means for releasing said shaft for a quick switch opening actuation of the latter by said spring means.

4. An electric switch as defined in claim 3 which includes an axially movable sleeve surrounding said shaft, and. in which said bevel is on the end of said sleeve presented toward said groove.

5;. An electric switch as defined in claim 3 in which a guide sleeve connected with said housing and extending substantially coaxially of said shaft comprises a retainer for said group of balls, and in which a thrust sleeve is slidable in said guide sleeve, said bevel being on the end of saidthrust sleeve presented toward said groove.

6. In an electric switch, a housing having a guide passage therein, stationary contact means in said housing, a shaft axially movable in said guide passage, movable contact means engageable with and disengageable from said stationary contact means by switch closing and switch opening axial movements of said shaft, said shaft having a shoulder thereon facing away from said contact means, means defining a groove surrounding said passage including a pair of divergent annular bevels forming side walls of the groove, an axially movable sleeve surrounding said shaft and carrying one of said bevels, an annular group of balls in said groove, a hollow actuating member disposed in a substantially coaxial surrounding relation to said shaft and being movable relative to said housing for imparting switch closing movement to said shaft, and spring means in surrounding relation to said shaft and subject to loading during the switch closing movement of said shaft and to partial unloading during movement of said actuating member in the switch opening direction, said group of balls being contractible into holding engagement with said shoulder by said bevels in response to the switch closing movement of said shaft and the loading of said spring means, said group of balls being expandable by said shoulder in response to the partial unloading of said spring means for releasing said shaft for a quick switch opening actuation of the latter by said spring means.

7. An electric switch as defined in claim 6 in which said shaft and actuating member have cooperating engageable portions, and wherein said actuating member has an initial position in which said engageable portions are in a spaced-apart relation.

8. An electric switch as defined in claim 6 in which an axial guide tube connected with said housing and surrounding said shaft forms a retainer for said group of balls, and in which said sleeve has a guided axial movement along the inside of said tube and said actuating member has a guided axial movement along the outside of said tube.

9. An electric switch as defined in claim 6 in which said shaft has a head thereon, and in which said spring means comprises a first spring disposed between said sleeve and said head and a second spring disposed between said sleeve and said actuating member.

10. An electric switch as defined in claim 6 in which said shaft has a head thereon and in which said spring means comprises a contact spring interposed between said shaft and said movable contact means and other spring means housed in said actuating member and seated against said sleeve, said other spring means comprising a first spring disposed between said-sleeve and said head and a second spring disposed between said sleeve and said actuating member.

References Cited in the file of this patent UNITED STATES PATENTS 2,086,752 Thornburg July 13, 1937 FOREIGN PATENTS 13,721 Great Britain Apr. 2, 1914 of 1913 115,727 Sweden 4 Jan. 29, 1946 

